How to replace all occurences of a variable in a string using javascript?

问题

I'm trying to replace all the occurrences of a variable in a string using javascript.

This is not working.:

var id = "__1";
var re = new RegExp('/' + id + '/g');
var newHtml = oldHtml.replace( re, "__2");

This is only replacing the first occurrence of id:

var id = "__1";
var newHtml = oldHtml.replace( id,"__2");

What am I doing wrong here?

Thanks

回答1:

When you instantiate the RegExp object, you don't need to use slashes; the flags are passed as a second argument. For example:

var id = "__1";
var re = new RegExp(id, 'g');
var newHtml = oldHtml.replace( re, "__2");

回答2:

You need the slashes before and after the string to replace (id).

Example

来源：https://stackoverflow.com/questions/1289330/how-to-replace-all-occurences-of-a-variable-in-a-string-using-javascript